IT WOULD STILL BE MURDER!Suppose it was Tuvix hitting the asteroid trying to escape Janeway fixing him?
Honestly, while I felt everyone else's pain there, I felt worst for poor Tuvix. (Personally, I didn't find him any more annoying than either Tuvok or Neelix separately. Most everyone on Voyager was at least a little annoying...but don't get me wrong, I liked them all well enough anyway, most of the time. It was a motley crew of misfits.) He was right, Tuvok and Neelix were both dead, and all they were really doing is trading one Frankenstein's monster for two, and deliberately killing a benign and unique being in the process. Janeway shouldn't have forced him into it, and others should have objected more strongly.
Obviously, permanently axing two of the main cast members wasn't on the cards, and the resultant character may not have been particularly suited to a continuing presence anyway. TUVIX HAD TO DIE!
I think what should have happened is, in the end it should have been his own choice to sacrifice himself for their return, and the benefit of their friends and loved ones, after initially refusing. It could still have been just as dramatic, we could still have felt his anguish at dying, and Janeway could even still have made up her mind as she did, and been about to inform him, when he instead pre-empted her by making the decision himself. She could have then felt disturbed by what she had almost done, having only been saved from it by Tuvix (which could also have been among his reasons for changing his mind, to spare her having to live with signing his death warrant.) Above all, she and the other characters could have expressed some measure of regret at the loss of their newfound friend, despite being ultimately consoled by the return of their old ones. I'm sure some might see that as a cop-out, but IMO such tweaks to the final scenes would have considerably improved the story for everyone concerned.
-MMoM
